From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH] Increase the tx queue to 512 descriptors to fix performance problem. Date: Wed, 09 Jan 2008 08:29:37 -0600 Message-ID: <4784DA51.7080507@us.ibm.com> References: <1199885016.4382.22.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm-devel , "virtualization@lists.linux-foundation.org" To: dor.laor@qumranet.com Return-path: In-Reply-To: <1199885016.4382.22.camel@localhost.localdomain> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: kvm.vger.kernel.org Dor Laor wrote: > Now that we have a host timer based tx wakeup it waits for 64 > packets or timeout before processing them. > This might cause the guest to run out of tx buffers while the host > holds them up. > There's a proper fix that Rusty added last night. > This is a temporal solution to quickly bring back performance to 800mbps. > But a better fix will soon be sent (its not the only problem). > How are you doing performance testing? Regards, Anthony Liguori > Signed-off-by: Dor Laor > --- > qemu/hw/virtio-net.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/qemu/hw/virtio-net.c b/qemu/hw/virtio-net.c > index 777fe2c..3d07b65 100644 > --- a/qemu/hw/virtio-net.c > +++ b/qemu/hw/virtio-net.c > @@ -293,7 +293,7 @@ void *virtio_net_init(PCIBus *bus, NICInfo *nd, int devfn) > n->vdev.update_config = virtio_net_update_config; > n->vdev.get_features = virtio_net_get_features; > n->rx_vq = virtio_add_queue(&n->vdev, 512, virtio_net_handle_rx); > - n->tx_vq = virtio_add_queue(&n->vdev, 128, virtio_net_handle_tx); > + n->tx_vq = virtio_add_queue(&n->vdev, 512, virtio_net_handle_tx); > n->can_receive = 0; > memcpy(n->mac, nd->macaddr, 6); > n->vc = qemu_new_vlan_client(nd->vlan, virtio_net_receive, >